Actuators of the pulling type, actuated by an explosive capsule, are disclosed in the following prior art U.S. Pat. Nos.: Leaman 3,024,592, Cordell 3,594,890, Williams 3,893,298. The Leaman patent discloses a pulling device embodying a housing having a cylinder in which a piston with a stem having an axial bore and radial ports for transferring the gases of explosion to the back side of the piston to produce retractive movement resulting in the stem being drawn into the housing. The explosive capsule is mounted in the head of the piston, and the reference does not disclose a transfer tube for directing the explosive gas into the piston. In the present invention, the explosive charge is contained in the cyliner head, thus simplifying the construction.